Document that streaming responses are already excluded from compression

Clarified in code comments and documentation that:
- Streaming responses (ReadableStream bodies) are rejected from StaticRoute
- They throw error at StaticRoute.fromJS():160 requiring buffered body
- Streams go through RequestContext, not StaticRoute
- Compression only applies to fully buffered static Response objects

This answers the "how does streaming work" question - it doesn't go through
StaticRoute at all, so compression is never applied to streams. No special
handling needed - the architecture naturally prevents it.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/bun.js/api/server/StaticRoute.zig

@@ -249,6 +249,9 @@ pub fn onRequest(this: *StaticRoute, req: *uws.Request, resp: AnyResponse) void
 }
 
 /// Try to serve a compressed variant if compression is enabled and conditions are met
+///
+/// NOTE: Streaming responses are NOT handled here - they're rejected at fromJS() line 160
+/// and go through RequestContext instead. This only compresses fully buffered static responses.
 fn tryServeCompressed(this: *StaticRoute, req: *uws.Request, resp: AnyResponse) bool {
     const server = this.server orelse return false;
     const config = server.compressionConfig() orelse return false;

src/http/CompressionConfig.zig

@@ -24,11 +24,11 @@ pub const COMPRESSION_ENABLED_BY_DEFAULT = false;
 /// - Only caches variants that clients actually request (lazy)
 /// - Compression often makes files smaller, but we store BOTH original and compressed
 ///
-/// ## Not Supported (Yet):
-/// - Dynamic routes (would need LRU cache with TTL and size limits)
-/// - Streaming responses
-/// - Cache eviction or memory limits
-/// - Selective caching per-route
+/// ## Not Supported:
+/// - **Dynamic routes** - Responses from fetch() handlers (would need LRU cache with TTL)
+/// - **Streaming responses** - ReadableStream bodies are rejected from static routes (see StaticRoute.zig:160)
+/// - **Cache eviction** - No memory limits or LRU eviction
+/// - **Per-route control** - Can only enable/disable globally or per-algorithm
 ///
 /// ## Usage:
 /// ```js